---
id: "openstack-placement"
type: "component"
kind: "coordination-service"
provider: "openstack"
category: "ops"
docs: "https://docs.openstack.org/placement/latest/"
url: "https://localhost:3000/catalogue/components/openstack-placement"
---

# OpenStack Placement

Tracks resource provider inventories, usages and traits so services can find where a workload fits.

| | |
|---|---|
| Provider | [openstack](https://localhost:3000/catalogue?provider=openstack) |
| Kind | [Coordination service](https://localhost:3000/catalogue/kinds/coordination-service) |
| Category | Operations |
| Official docs | [https://docs.openstack.org/placement/latest/](https://docs.openstack.org/placement/latest/) |

## Properties

| property | type | values | required | kind default | this component |
|---|---|---|---|---|---|
| `consensus` | enum | `none`, `raft`, `paxos`, `zab` | no | "none" | inherited |
| `managed` | boolean | — | no | false | **false** |
| `nodes` | integer | — | no | — | inherited |
| `replicated` | boolean | — | no | false | inherited |
| `resourceClasses` | boolean | — | no | true | inherited |
| `role` | enum | `metadata`, `lock`, `discovery`, `placement`, `sharding`, `leader-election`, `config` | yes | — | **"placement"** |
| `standalone` | boolean | — | no | true | inherited |
| `traits` | boolean | — | no | true | inherited |

Bold values are the ones this component pins.

## Rules that apply · 2

### Shared dependency without redundancy `shared-dependency-without-redundancy` (error)

- Page: https://localhost:3000/catalogue/rules/shared-dependency-without-redundancy.md
- Why: The design requires redundant discovery, but this DNS or coordination service, which everything depends on, runs on a single provider or a single replica. Its failure is the whole system's failure.
- Applies to: every node of kind dns or coordination-service
- Message: Shared dependency '{{node.id}}' is not redundant, but the design requires redundant discovery.

It fires when:

- all of these hold:
  - the design requirement `availability.discoveryRedundant` is true
  - any of these hold:
    - the node's `redundantProviders` is false
    - the node's `replicated` is false

### Stateful engine pinned to a single zone `stateful-engine-pinned-to-single-zone` (error)

- Page: https://localhost:3000/catalogue/rules/stateful-engine-pinned-to-single-zone.md
- Why: A matching engine, coordination service or event store living in exactly one availability zone, with no failover and no replication, is lost with that zone. Everything that depends on it stops with it.
- Applies to: every node of kind matching-engine, coordination-service or event-store
- Message: '{{node.id}}' is pinned to a single availability zone with no failover or replication.

It fires when:

- all of these hold:
  - the node sits inside exactly 1 availability-zone group
  - any of these hold:
    - the node's `failover` is "none"
    - the node's `replicated` is false
    - the node's `replication` is "none"

## Other products of the same kind · 17

- [Microservices Engine](https://localhost:3000/catalogue/components/alibaba-mse.md) `alibaba-mse` — alibabacloud
- [AWS Cloud Map](https://localhost:3000/catalogue/components/aws-cloud-map.md) `aws-cloud-map` — aws
- [Azure Arc](https://localhost:3000/catalogue/components/azure-arc.md) `azure-arc` — azure
- [Azure Device Registry](https://localhost:3000/catalogue/components/azure-device-registry.md) `azure-device-registry` — azure
- [Durable Objects](https://localhost:3000/catalogue/components/cloudflare-durable-objects.md) `cloudflare-durable-objects` — cloudflare
- [Apache Helix](https://localhost:3000/catalogue/components/apache-helix.md) `apache-helix` — default
- [Consul](https://localhost:3000/catalogue/components/consul.md) `consul` — default
- [Generic coordination service](https://localhost:3000/catalogue/components/coordination-service.md) `coordination-service` — default
- [etcd](https://localhost:3000/catalogue/components/etcd.md) `etcd` — default
- [Eureka](https://localhost:3000/catalogue/components/eureka.md) `eureka` — default
- [Nacos](https://localhost:3000/catalogue/components/nacos.md) `nacos` — default
- [Oxia](https://localhost:3000/catalogue/components/oxia.md) `oxia` — default
- [Apache ZooKeeper](https://localhost:3000/catalogue/components/zookeeper.md) `zookeeper` — default
- [Service Directory](https://localhost:3000/catalogue/components/google-service-directory.md) `google-service-directory` — gcp
- [Endpoints](https://localhost:3000/catalogue/components/k8s-endpoints.md) `k8s-endpoints` — k8s
- [OpenStack Blazar](https://localhost:3000/catalogue/components/openstack-blazar.md) `openstack-blazar` — openstack
- [OpenStack Cyborg](https://localhost:3000/catalogue/components/openstack-cyborg.md) `openstack-cyborg` — openstack

## Use it in a design

```yaml
nodes:
  - { id: "openstack-placement", component: "openstack-placement" }
```

## Source (`component` YAML, verbatim)

```yaml
# yaml-language-server: $schema=../../schema/component.schema.json
# OpenStack Placement: "a REST API stack and data model used to track resource provider
# inventories and usages, along with different classes of resources" ("Placement API").
# It records resource providers (compute nodes, storage pools, IP allocation pools), their
# inventories in resource classes such as VCPU, MEMORY_MB and DISK_GB, and qualitative traits;
# Nova and other services ask it where a workload can fit. Extracted from Nova into its own
# repository in Stein (19.0.0) after arriving in Newton (14.0.0).
schemaVersion: "1"
type: "component"
id: "openstack-placement"
kind: "coordination-service"
provider: "openstack"
docs: "https://docs.openstack.org/placement/latest/"
defaults:
  role: "placement"
  managed: false
properties:
  resourceClasses:
    type: "boolean"
    default: true
  traits:
    type: "boolean"
    default: true
  standalone:
    type: "boolean"
    default: true
```

Human page: https://localhost:3000/catalogue/components/openstack-placement